Prohairetic Deontic Logic (PDL)

  • Leendert W. N. van der Torre
  • Yao-Hua Tan
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1489)


In this paper we introduce Prohairetic Deontic Logic (PDL), a preference-based dyadic deontic logic. An obligation ‘α should be (done) if β is (done)’ is true if (1) no ¬αβ state is as preferable as an αβ state and (2) the preferred β states are α states. We show that the different elements of this mixed representation solve different problems of deontic logic. The first part of the definition is used to formalize contrary-to-duty reasoning, that for example occurs in Chisholm’s and Forrester’s notorious deontic paradoxes. The second part is used to make dilemmas inconsistent. PDL shares the intuitive semantics of preference-based deontic logics without introducing additional semantic machinery such as bi-ordering semantics or ceteris paribus preferences.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Leendert W. N. van der Torre
    • 1
  • Yao-Hua Tan
    • 2
  1. 1.IRITPaul Sabatier UniversityToulouseFrance
  2. 2.EuridisErasmus University RotterdamThe Netherlands

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